Material processing device



Dec. 8, 1964 J. A. REISING MATERIAL PROCESSING DEVICE Filed Dec. 17, 1962 2 Sheets-Sheet l i 30 32 I0 I8 28 1 r 50 FIG. I 22 FI G. 3 4 4- INVENTOR.

JOSEPH A. REISING M %M A TTORNEYJ:

J. A.RE|S|NG MATERIAL PROCESSING DEVICE Dec. 8 1964 2 sheets -sheet 2 Filed Dec. 17, 1962 6 G 5 I l E El m w F I 5(M 0 w MY M m 7. m a w lmw v M Q Q w Mu M "4 3 II VVENTOR. JOSEPH A. REISING ATTORNEYS United States Patent 3,163,395 MATERIAL PROCESSING DEVICE Joseph A. Raising, Sewiclrley, Pa, assignor to St. Joseph Lear; Company, New York, N.Y., a corporation of New Filed Dec. 17, 1962, Ser- No. 245,310 7 Claims. (Cl. 259-3) This invention relates to improvements in material mixing machines. In particular, the invention relates to an apparatus for thorough, uniform, and intimate dry mixing of relatively fine powders.

tion to provide an apparatus for uniformity mixing dry powders without altering the physical characteristics of the powders to be mixed.

A further object is to provide an apparatus for efiecting dry mixing of fine powders that is equally applicable to continuous or batch processing.

A further object to to provide an improved apparatus for intimately and uniformly mixing dry powders that is commercially feasible and does not require constant attention by skilled operators.

A further object is to provide an improved apparatus for continuous or batch-wise mixing of dry powders without grinding or disintergration of the particulate constituents of the powders.

These and other objects and advantages are provided by a mixing device for powders comprising a rigid cylindrical shell having open ends, means for mounting said shell for rotation with the longitudinal axis thereof generally horizontal, a resilient liner within said shell and extending from end to end thereof, said resilient liner mounted in spaced relation to the inner cylindrical wall of said shell and maintained out of contact with the cylindrical wall of the shell during normal operation of the mixing device, a plurality of resilient elements maintained within said liner, and means for rotating said shell and its attached liner about the longitudinal axis thereof; and by a method of mixing dry powders comprising introducing the powders to be mixed into a confined zone having a yieldable surface, maintaining a plurality of resilient bodies within the confined zone and in contact with the powders to be mixed, and causing relative movement only between the powders, the resilient bodies, and the yieldable surface during the mixing of the powders.

The invention will be more particularly described with reference to the illustrative embodiments to the present invention wherein:

FIG. 1 is a plan view of apparatus constructed in accordance with the teachings of the present invention;

FIG. 2 is an enlarged fragmentary partial sectional view of the apparatus illustrated in FIG. 1 with compressed air maintained between the liner and the shell;

FIG. 3 is a view similar to that illustrated in FIG. 2 with a charge of powders to be mixed and resilient mixing bodies within the mixing apparatus and a reduced pressure maintained between the shell and the liner;

FIG. 4 is a section substantially on line 4-4 of FIG. 3 illustrating the mixing action which takes place during rotation of the apparatus illustrated in FIG. 3;

FIG. 5 is a view similar to that illustrated in FIG. 3 of a modified form of the present invention;

FIG. 6 is a view similar to that illustrated in FIG. 3 of a further modified form of the invention; and

FIG. 7 is a section substantially on line 77 of FIG. 6 illustrating the action of the resilient liner, the resilient material spacing the liner from the mixing drum shell and 3,160,395 Patented Dec. 8, 1964 "ice the resilient mixing elements during rotation of the mixing apparatus illustrated in FIG. 6.

Referring to the drawings and, in particular, to FIGS. 1 through 4, It) generally indicates an improved mixing device incorporating the principles of the present invention. The mixing device includes a rigid drum having a cylindrical casing or shell 12 mounted adjacent its ends 14 and 16 for rotation with the longitudinal axis of the cylindrical casing or shell 12 generally horizontal.

The mounting means for the cylindrical shell 12 include a ring member 18 at end 14 and a ring member 20 at end 16. The ring members 18 and 20 are supported on standards 22 and 24, respectively. The standards 22 and 24 are provided with roller elements generally designated 26 which engage their respective ring member. The shell 12 is rotated by motor means 28 through a pinion gear 32 connected to the output shaft 30. The pinion 32 engages a ring gear 34 secured to the shell 12.

In the illustrated form of the invention, end 14 of the mixing device is the feed end and is provided with a particulate material inlet chute generally designated 36 while the opposite end 16 is the material outlet end and is provided with screen means 38, the function of which will be more fully described hereinafter. The cylindrical shell 12 is provided with a resilient liner 4%) which extends from end 14 to end 16 in spaced relationship to the inner wall 42 of the cylindrical shell 12. The resilient liner 40 is attached under tension to the inwardly tapered end portions 44 and 46 of the rigid drum and is constructed of natural or synthetic elastomeric material. The open ends paratus is illustrated as being under a positive pressure and in FIG. 3 under a negative pressure.

When a positive pressure is employed between the inner wall 42 of the shell 12 and the outer wall of the liner 40,

the resilient cushioning, of the powder to be mixed and V the resilient mixing elements, is brought about by the combined action of the elastomeric material of the liner and the positive pneumatic pressure. Where a negative or ambient pressure is maintained between the inner wall 42 of the shell 12. and the outer wall of the resilient sleeve 40, the primary cushioning is brought about by the resiliency of the liner itself.

The assembly also includes a plurality of resilient mixing elements 54 which are maintained in the mixing chamber defined by the Wall of the resilient liner 40. The resilient elements 54 are illustrated in FIGS. 3 and 4 as comprising relatively small resilient spheres or balls. The

exact shape and size of the resilient mixing elements 54 is mixing elements is not critical in general, very satisfactory results are obtained when the cumulative volume of the resilient elements is from about 25 to about 55% of the volume encased by the resilient liner and when the elements are either sperical or cylindrical in shape. If spherical elements are employed preferably they should be from about 1 to about 4 inches in diameter, and if cylindrical, l to 4 inches in diameter and from 1 to about 4 inches high. Within this range very satisfactory rethe critical point, the resilient balls and the charge drop as shown in FIG. 4 bumping against other resilient balls sults are obtained if the charge of the powders to be mixed comprises about 25% of the volume encased by the resilient liner.

Where the mixing device is'of the continuous type, standard 24 at the discharge end islower than the standard 26 at the inlet end to provide a positive slope for the shell 12 whereby upon rotation of theshell, material entering the'drum at end 14 will eventually exit from the drum at end 15 by gravity. I

Referring to FIG. of the drawings, a modified form of the apparatus of the present invention is illustrated and structures shown therein corresponding to structures shown in FIGS. 1 through 4 are designated with primed reference characters. In FIG. 5 the cylindrical shell 12' is mounted for rotation about a generally horizontal axis on a pair of rim members, the rim member 26 at the discharge'end 16' being illustrated in the drawing. The drum is caused to rotate by drive means coupled to the ring gear 34'. The mixing chamber of the mixingdevice lilis provided with a-resilient liner or sleeve 40 which is attached to the inlet and the outlet ends of the shell 12' to maintain the charge of material to be mixed and the resilient mixing elements 54' out of contact with the non-resilient inner surface of the shell 12'.

As in the prior illustrated form of the apparatus, means are provided for maintaining ambient, reduced or positive pressure between the inner surface of the shell 12 and the outer surface of the resilient sleeve 49'. In this form of the invention the means. for maintaining ambient negative or positive pressure insaid zone comprises an annular generally U-shaped channel member 60 secureds'uch as by welding to the cylindrical outer surface of the. shell 12. The U-shaped channel member 6% is in register with a further annular U-shaped channel member 62. Flexible sealing means illustrated at 64 are secured to either the annular U-shaped channel member 66 or to the U-shaped channel member 62 to provide a positive seal during rotation of the drum or shell 12 and its attached channel member. 60 while the annular channel the priorform of the invention, a conventional pressure gauge 50 may be included in the assembly so that the operator may readily determine the positive or the negative pressure maintained between the inner surface of 'the shell 12 and the outer surface of the resilient liner or sleeve 40'.

assembly during the mixing operation. 1 V

The operation ,of the forms of the invention shown in poses of illustration, the form operating under a positive pressure will be described. The apparatus .illus-' trated in FIG. 1 is charged with a plurality ofsphei'ical synthetic rubber balls and the pressure between the inner wall of the shell 12 and the outer wall of the sleeve dtiis adjusted such that'with a predetermined load of resilient balls and the material to be mixed, the resilient sleeve is maintained out of contact with the cylindrical outer surface of the shell. A charge of American Process Zinc Oxide, of particle size of about .27.micron, and a fine ultramarine blue is fed into the apparatus through the inlet chute means 36 as the drum rotates. The speed of.

rotation of the apparatus is adjusted such that the resilient balls and the powder tobe mixed are carried to a position as illustrated in FIG. 4 before the powder and the resili- With this arrangement the operator may readily control the resilient cushioning provided by the.

silient balls, the powder and the resilient liner.

then positioned adjacent the lowermost surface of the resilient sleeve, thereby applying a force on the powder a to effect an intimate physical mixing of the particles in contactwith the resilient objects at the time of impact. After impact, the resiliency of the'rubber balls causes them to resume their normal shape, thereby removing any of the mixture which might otherwise adhere thereto. This process is repeated over and over again between the resilient objects and the powders to be mixed resulting in a thorough, uniform and intimate mixture. The resilient liner prevents caking or accumulation of the powders on the inside of the containerand at the same time aids in the mixing processwhere impacts occur between the re- Powder passing through the mixing chamber is removed therefrom through. the screened outlet,

The powders discharged from the discharge end of the apparatus were examined under a; microscope and the powders were found to be thoroughly, uniformly and intimate-1y mixed and the'mixturewas found to be soft with substantially no change in its apparent density and no change in the particle size rangeof the charged powders.

. Referring particularly to FIGS. 6 and 7, a further form of apparatus is illustrated wherein elements corresponding to elements illustrated in FIGS. 1 through 4 are provided with double primed reference characters.

The mixing device 10" generally comprises'an outer rigid cylindrical shell 12" mounted for rotation with its longitudinal axis generally horizontal. At opposite ends of the drum ring or rim members are provided with the ring member 20" at the discharge end 16". being illustrated. Rotation of the drum is brought about as illustrated in FIGS. 1 through 4 by a motor driven pinion engaging the ring gear 34". Withinthe drum or shell 12" is a resilient liner 4t)" with the ends of the resilient liner l4" and 16".

Between the outer surface of the resilient liner 40" and the inner non-resilient surface of the shell 12" is maintained a cushioning layer of elastomeric material 89 such as foamor sponge rubber or plastic which functions to permit distortion of the resilient liner 40 as be seen that improved mixing apparatus are provided the mixing device is rotated as illustrated in FIG. 7. Comparing FIG. 7 with FIG. 4 of the drawings, it will be 7 seen that the amount and the elasticity of the resilient,

material 80 is such that the outer surface of liner 4t) does not come in contact with the non-resilient inner surface-of the shell 12" and that the effect of the elastomeric material 80 is comparable to the forms or the invention wherein the space between the outer surface of the resilient sleeve and the inner surface of the shell are maintained under a positive or negative pressure.

From/the foregoing description considered with the illustnated embodiments of the present invention, it will a which fully accomplishes the aims'and objects herein- FIGS. 1 through 5 is substantially identical and, for purent balls drop to the lower surface of the resilient sleeve.

above set forth. It will be appreciated by those skilled in the art that various modifications may be made in the specific formof the appamatus without departing from the scope of the appended claims; For example, Where the mixing device is of the batch type, the continuous inlet chutes and the continuous outlet screen means would be replaced by removable solid head members whereby a charge of material would be inserted within the mixing apparatus and removed after a predetermined period of rotation. 1

I claim: 1. A dry powder mixing device comprising a rigid cylindrical shell having open ends, means mounting said shell for rotation with the longitudinal thereofgenerally horizontaL'a resilient liner within said shell and extending from end to end thereof, said resilient liner mounted in spaced relation to the inner cylindrical wall of I said shell and maintained out of contactwith the cylindrical wall of the shell during normal operation of the device, a plurality of resilient elements maintained within said liner, and means for rotating said shell and its attached liner about the longitudinal axis thereof and cansing relative movement between the powders, the resilient bodies, and the yieldable surface during the mixing.

2. A dry powder mixing device comprising a rigid cylindrical shell having open ends, means mounting said shell for rotation with the longitudinal axis thereof generally horizontal, a resilient liner within said shell and extending from end to end thereof, said resilient liner mounted in spaced relation to the inner cylindrical wall of said shell and maintained out of contact with the cylindrical wall of the shell during normal operation of the device, a plurality of resilient elements maintained within said liner, means for continuously feeding particulate material to be mixed at one end opening of said cylindrical shell, and means for continuously removing mixed particulate material at the other end opening of said shell, and means for rotating said shell and its attached liner about the longitudinal axis thereof and causing relative movement between the powders, the resilient bodies, and the yieldable surface during the mixing.

3. A dry powder mixing device comprising a rigid cylindrical shell having open ends, means mounting said shell for rotation with the longitudinal axis thereof generally horizontal, a resilient liner within said shell and extending from end to end thereof, said resilient liner mounted in spaced relation to the inner cylindrical wall of said shell and maintained out of contact with the cylindrical wall of the shell during normal operation of the device, a plurality of resilient elements maintained within said liner, means for continuously feeding particulate material to be mixed at one end opening of said shell, means for continuously removing mixed particulate material at the other end of said shell, said means for removing the mixed particulate material from said other end opening including screen means closing said other opening, the

' openings in said screen means being smaller than the crosssection of the resilient elements maintained said liner, and means for rotating said shell and its attached liner about the longitudinal axis thereof and causing relative movement between the powders, the resilient bodies, and the yieldable surface during the mixing.

4. A dry powder mixing device comprising a rigid cylin drical shell having open ends, means mounting said shell for rotation with the longitudinal axis thereof generally horizontal, a resilient liner within said shell and attached adjacent the ends thereof, said resilient liner mounted in spaced relation to the inner cylindrical wall of said shell, means coopenating with said resilient liner maintaining said liner out of contact with the cylindrical wall of the shell during normal operation of the device, saidmeans cooperating with the resilient liner maintaining the resilient liner out of contact with the cylindrical wall of the shell comprising means for maintaining a positive pressure between the outer surface of the resilient liner and the inner surface of the cylindrical shell, a plurality of resilient elements maintained within said liner, and means for rotating said shell and its attached liner about the longitudinal axis thereof and causing relative movement between the powders, the resilient bodies, and the yieldable surface during the mixing.

5. A dry powder mixing device comprising a rigid cylindrical shell having open ends, means mounting said shell for rotation with the longitudinal axis thereof generally horizontal, a resilient liner within said shell and attached adjacent the ends thereof, said resilient liner mounted in spaced relation to the inner cylindrical wall of said shell, means cooperating with said resilient liner maintaining said liner out of contact with the cylindrical wall of the shell during normal operation of the device, said means cooperating with the resilient liner maintaining the resilient liner out of contact with the cylindrical wall of the shell comprising means for maintaining a negative pressure between the outer surface of the resilient liner and the inner surface of the cylindrical shell, a "plurality of resilient elements maintained within said liner, and means for rotating said shell and its attached liner about the longitudinal vaxis thereof and causing relative movement between the powders, the resilient bodies, and the yieldable surface during the mixing.

6. A dry powder mixing device comprising a rigid cylindrical shell having open ends, means mounting said shell 1 liner and the shell, a plurality of resilient elements main:

tained Within said liner, means for continuously feeding particulate material to be mixed at one end opening of said cylindrical shell, and means for continuously removing mixed particulate material at the other end opening of said shell, and means for rotating said shell and its attached liner about the longitudinal axis thereof and causing relative movement between the powders, the res silient bodies, and the yieldable surface during the mixing.-

7. A dry powder mixing device comprising a rigid cylindrical shell having open ends, means mounting said shell for rotation with the longitudinal axis thereof generally horizontal, a resilient liner within said shell and extending from end to end thereof, said resilient liner mounted in spaced relation to the inner cylindrical wall of said shell and maintained out of contact with the cylindrical wall of the shell during normal operation of the device, a plurality of resilient balls maintained within said liner, and means for rotating said shell and its attached liner about the longitudinal axis thereof and causing relative movement between the powders, the resilient bodies, and the yieldable surface during the mixing.

References Cited by the Examiner UNITED STATES PATENTS 2,101,866 12/37 Merritt 68-29 2,227,905 1/41 Keenoy 220-63 2,603,832 7/52 Clark et a1.

2,711,557 6/55 Russell. 2,872,386 2/ 59 Aspegren 259-3 X 2,970,042 1/ 61 Lagerwey 220-63 X 3,030,081 4/62 Wilson et a1. 259-81 X 3,087,707 4/63 Moonan 259-29 3,132,846 5/64 'Siddall 259-3 I FOREIGN PATENTS 633,127 12/61 Canada.

1,204,067 8/59 France.

CHARLES A. WILLMUTH, Primary Examiner. 

1. A DRY POWDER MIXING DEVICE COMPRISING A RIGID CYLINDRICAL SHELL HAVING OPEN ENDS, MEANS MOUNTING SAID SHELL FOR ROTATION WITH THE LONGITUDINAL AXIS THEREOF GENERALLY HORIZONTAL, A RESILIENT LINER WITHIN SAID SHELL AND EXTENDING FROM END TO END THEREOF, SAID RESILIENT LINER MOUNTED IN SPACED RELATION TO THE INNER CYLINDRICAL WALL OF SAID SHELL AND MAINTAINED OUT OF CONTACT WITH THE CYLINDRICAL WALL OF THE SHELL DURING NORMAL OPERATION OF THE DEVICE, A PLURALITY OF RESILIENT ELEMENTS MAINTAINED WITHIN SAID LINER, AND MEANS FOR ROTATING SAID SHELL AND ITS ATTACHED LINER ABOUT THE LONGITUDINAL AXIS THEREOF AND CAUSING RELATIVE MOVEMENT BETWEEN THE POWDERS, THE RESILIENT BODIES, AND THE YIELDABLE SURFACE DURING THE MIXING. 